Rock City Underground is a former limestone mine on a bluff above the Mississippi, downstream from St. Louis, near the town of Valmeyer, Illinois. It is a location for the National Archives and Records Administration, which leased 400,000 square feet to house federal personnel records in 2008. Another major tenant is Blue Line Food Distributors, which handles the Little Caesars Pizza brand. So far around 1 million of the 6 million square feet of the mine has been redeveloped.